When it comes to winter wheat, fusarium head blight (FHB) likes lots of spring moisture but cool temperatures can slow development of the disease.
Cool and wet weather are two things Ontario's wheat crop has seen plenty of in 2025. On this episode of the RealAgriculture Wheat School, Bayer Crop Science agronomist Kurtis Pilkington looks at the role weather could play in the potential development of FHB and other leaf diseases this spring. He also shares timing and application strategies for T3 fungicide to protect the crop as heads emerge in wheat fields across the province.
In this field, Pilkington notes that the wheat head is just coming out of the the boot. At this stage, he estimates that the plants are two days away from Day 0 — that's when the head is fully out of the boot and growers need to start thinking about fungicide application. "Optimal timing is really going to be starting two days after that, up to about five days — when you first get those flowers in the middle of the wheat head, until you get to about 50 per cent through flowering." Overall, the general application window extends to about Day 8.
Pilkington notes that research conducted by Dr. Dave Hooker at University of Guelph indicates that about 75 per cent of the time growers will see a 5.5 bushel per acre yield advantage when to applying a T3 fungicide; in higher disease pressure scenarios the average is eight bushels.
For Pilkington, timing the application is critical for success. "The only way you're really going to hit that properly is if you're out scouting your fields. The easiest way... is to look for when 75 per cent of the heads in the field are at 50 per cent flowering. If you hit that, that's perfect. That's the window that you should be trying to go for."
In the video, Pilkington discusses the need for growers to be on the lookout for stripe rust and other leaf diseases. He also reviews spraying fundamentals including water volumes, droplet size, boom height and wind speed at timing of application.
Tap here for more Wheat School videos.
